The present invention relates to a nicotine immunogen, to a 5- or 6-nicotinyl-linker-protein and its use as a medicament and a pharmaceutical composition comprising the 5- or 6-nicotinyl-linker-protein, and to a method of prophylactic and/or therapeutic immunological treatment of nicotine dependence from tobacco products to achieve harm reduction.
Due to the vast number of tobacco users/smokers in the world who want to get rid of their dependence, there is a large market for products helping them to reach their goal or at least result in harm reduction.
One approach is to develop a vaccine/immunogen that in an individual can elicit antibodies which strongly bind to administered/inhaled nicotine and block its effect before it reaches their central nervous system. The idea is that if the individual does not experience the expected stimulating effect of nicotine administration/smoking, the interest in administering a tobacco product, such as moist snuff, or lighting a cigarette will cease (extinction/prevention).
A complementary approach is to develop an immunogen that in an individual can elicit antibodies which moderately or weakly bind to administered/inhaled nicotine and enhance/prolong its effect in their central nervous system. The idea is that if the individual experiences the expected stimulating effect of nicotine administration/smoking during a prolonged period of time, the interest in a renewed administration of a tobacco product, such as moist snuff, or lighting a cigarette will be postponed and the medical consequences of the tobacco product consumption will be reduced.
Both of the above mentioned approaches use immunogens which in an individual induces an immunological response which leads to harm reduction.
In the prior art there are papers describing immunoassays using antibodies directed to nicotine, but such antibodies have not been suggested for any medical use (See e.g. Castro A. and Monji N. Res. Comm. Chem. Path. Pharmacol. 1986,51, 393-404.)
The idea of treating nicotine dependence with a vaccine is not new, since it is comprised by earlier general disclosures of manufacturing vaccines against drugs which may cause a dependence (see e.g. EP-B1-0 496 839, exemplified by morphine; and WO 96/30049, exemplified by cocaine).
A paper disclosing active immunization to alter nicotine distribution was recently published (Hieda Y. et al, J. Pharmacol. and Exp. Therap. 1997,283, 1076-1081). The immunogen used in the experiments was (xc2x1)-6-(carboxymethyl-ureido)-nicotine linked to keyhole limpet hemocyanin.
Recently, the international patent application WO 98/14216 was published (Sep. 04, 1998). This application claims a large number of hapten-carrier conjugates based on the nicotine molecule and the common structural feature of the compounds seems to be that all of the hapten molecules contain a terminal carboxylic acid group which is then conjugated to the carrier. No in vivo testing has been disclosed for the alleged drug abuse treatment.
The present invention is directed to a nicotine immunogen comprising a 5- or 6-nicotinyl-linker-carrier protein having the formula 
wherein
X is xe2x80x94NHxe2x80x94COxe2x80x94 or xe2x80x94NHxe2x80x94 or xe2x80x94Cxe2x89xa1Cxe2x80x94 or xe2x80x94CHxe2x95x90CHxe2x80x94 or xe2x80x94CH2xe2x80x94;
Y is xe2x80x94(CH2)kxe2x80x94 or xe2x80x94(CH2)mxe2x80x94C6H10xe2x80x94(CH2)nxe2x80x94 or xe2x80x94(CH2)mxe2x80x94C6H4xe2x80x94(CH2)nxe2x80x94
wherein k=0-20, m=0-6, and n=0-6, when
Z is xe2x80x94NHxe2x80x94,
with the provisio that X is not xe2x80x94NHxe2x80x94COxe2x80x94 when Y is (CH2)5 and Z is xe2x80x94NHxe2x80x94,
and
X is xe2x80x94NHxe2x80x94COxe2x80x94 or xe2x80x94Cxe2x89xa1Cxe2x80x94 or xe2x80x94CHxe2x95x90CHxe2x80x94 or xe2x80x94CH2xe2x80x94,
Y is xe2x80x94(CH2)mxe2x80x94C6H10xe2x80x94(CH2)nxe2x80x94 or xe2x80x94(CH2)mxe2x80x94C6H4xe2x80x94(CH2)nxe2x80x94
wherein m=0-6, and n=0-6, when
Z is xe2x80x94COxe2x80x94,
and
X is xe2x80x94Cxe2x89xa1Cxe2x80x94 or xe2x80x94CHxe2x95x90CHxe2x80x94,
Z is xe2x80x94COxe2x80x94, when
Y is xe2x80x94(CH2)kxe2x80x94
wherein k=0-20.
In a preferred embodiment of the invention the 5- or 6-nicotinyl-linker-carrier proteins are selected from compounds wherein k=1-8, m=0-3 and n=0-3.
Other names for the 5- or 6-nicotinyl-linker-carrier protein are 5-(1-methyl-2-pyrrolidinyl)-2- or 3-pyridinyl-linker-carrier protein and 5-(N-methyl-2-pyrrolidinyl)-2- or 3-pyridinyl-linker-carrier protein.
The carrier protein of the 5- or 6-nicotinyl-linker-carrier protein of the invention may be selected from pharmaceutically acceptable proteins which coupled to a hapten are suitable for eliciting antibodies in humans, and is for example selected from the group consisting of keyhole limpet hemocyanin (KLH), tetanus toxoid, diphtheria toxoid, non-toxic mutant diphtheria toxoid CRM197, outer membrane protein complex (OMPC) from Neisseria meningitidis, the B subunit of heat-labile Escherichia coli, and recombinant exoprotein A from Pseudomonas aeruginosa (rEPA).
The present invention is further directed to a 5- or 6- nicotinyl-linker-carrier protein having the formula 
wherein
X is xe2x80x94NHxe2x80x94COxe2x80x94 or xe2x80x94NHxe2x80x94 or xe2x80x94Cxe2x89xa1Cxe2x80x94 or xe2x80x94CHxe2x95x90CHxe2x80x94 or xe2x80x94CH2xe2x80x94;
Y is xe2x80x94(CH2)kxe2x80x94 or xe2x80x94(CH2)mxe2x80x94C6H10xe2x80x94(CH2)nxe2x80x94 or xe2x80x94(CH2)mxe2x80x94C6H4xe2x80x94(CH2)nxe2x80x94
wherein k=0-20, m=0-6, and n=0-6, when
Z is xe2x80x94NHxe2x80x94,
with the provisio that X is not xe2x80x94NHxe2x80x94COxe2x80x94 when Y is (CH2)5 and Z is xe2x80x94NHxe2x80x94,
and
X is xe2x80x94NHxe2x80x94COxe2x80x94 or xe2x80x94Cxe2x89xa1Cxe2x80x94 or xe2x80x94CHxe2x95x90CHxe2x80x94 or xe2x80x94CH2xe2x80x94,
Y is xe2x80x94(CH2)mxe2x80x94C6H10xe2x80x94(CH2)nxe2x80x94 or xe2x80x94(CH2)mxe2x80x94C6H4xe2x80x94(CH2)nxe2x80x94
wherein m=0-6, and n=0-6, when
Z is xe2x80x94COxe2x80x94,
and
X is xe2x80x94Cxe2x89xa1Cxe2x80x94 or xe2x80x94CHxe2x95x90CHxe2x80x94,
Z is xe2x80x94COxe2x80x94, when
Y is xe2x80x94(CH2)kxe2x80x94
wherein k=0-20.
Also in this aspect of the invention the carrier protein may be selected from the group consisting of keyhole limpet hemocyanin (KLH), tetanus toxoid, diphtheria toxoid, non-toxic mutant diphtheria toxoid CRM197, outer membrane protein complex (OMPC) from Neisseria meningitidis, the B subunit of heat-labile Escherichia coli, and recombinant exoprotein A from Pseudomonas aeruginosa (rEPA).
Further, the invention is directed to the new 5- or 6-nicotinyl-linker-carrier proteins according to the invention for use as a medicament, such as the immunizing component in a vaccine.
One compound excluded from the compounds of the above formula of the invention has been previously disclosed by Castro A. and Monji N. (ibid.), namely the 6-nicotinyl-linker-carrier protein wherein the carrier protein is bovine serum albumin and the linker is xe2x80x94NHxe2x80x94COxe2x80x94(CH2)5xe2x80x94NHxe2x80x94. However, this compound has not been suggested for medical use.
The invention is additionally directed to a pharmaceutical composition comprising a 5- or 6-nicotinyl-linker-carrier protein according to the invention and a pharmaceutically acceptable vehicle.
The vehicle in the pharmaceutical composition needed for administration of the immunogenic compound of the invention may be selected from known pharmaceutically acceptable vehicles, such as physiological saline solution or other suitable vehicle e.g. disclosed in the European or US Pharmacopoeia.
The pharmaceutical composition according to the invention may further comprise an adjuvant, which naturally must be pharmaceutically acceptable for human use, such as aluminum phosphate and aluminum hydroxide.
The invention is furthermore directed to a method of prophylactic and/or therapeutic immunological treatment of nicotine dependence from tobacco products to achieve harm reduction in an individual comprising administration of a 5- or 6-nicotinyl-linker-carrier protein having the formula 
wherein
X is xe2x80x94NHxe2x80x94COxe2x80x94 or xe2x80x94NHxe2x80x94 or xe2x80x94Cxe2x89xa1Cxe2x80x94 or xe2x80x94CHxe2x95x90CHxe2x80x94 or xe2x80x94CH2xe2x80x94;
Y is xe2x80x94(CH2)kxe2x80x94 or xe2x80x94(CH2)mxe2x80x94C6H10xe2x80x94(CH2)nxe2x80x94 or xe2x80x94(CH2)mxe2x80x94C6H4xe2x80x94(CH2)nxe2x80x94
wherein k=0-20, m=0-6, and n=0-6, when
Z is xe2x80x94NHxe2x80x94,
with the provisio that X is not xe2x80x94NHxe2x80x94COxe2x80x94 when Y is (CH2)5 and Z is xe2x80x94NHxe2x80x94,
and
X is xe2x80x94NHxe2x80x94COxe2x80x94 or xe2x80x94Cxe2x89xa1Cxe2x80x94 or xe2x80x94CHxe2x95x90CHxe2x80x94 or xe2x80x94CH2xe2x80x94,
Y is xe2x80x94(CH2)mxe2x80x94C6H10xe2x80x94(CH2)nxe2x80x94 or xe2x80x94(CH2)mxe2x80x94C6H4xe2x80x94(CH2)nxe2x80x94
wherein m=0-6, and n=0-6, when
Z is xe2x80x94COxe2x80x94,
and
X is xe2x80x94Cxe2x89xa1Cxe2x80x94 or xe2x80x94CHxe2x95x90CHxe2x80x94,
Z is xe2x80x94COxe2x80x94, when
Y is xe2x80x94(CH2)kxe2x80x94
wherein k=0-20,
to said individual in antibody-eliciting amounts for eliciting antibodies binding to nicotine molecules.
For a specific individual the antibody-eliciting amount will be found empirically by subjective experience of the stimulating effect in error and trial tests, or will be suggested by the manufacturer or physician.
In a preferred embodiment of this aspect of the invention the administration is repeated at intervals to enhance the titre of antibodies binding to nicotine molecules in said individual. The individual is preferably a human even though the invention would function if another mammal should be treated. This could of course be the case if laboratory animals were used for testing purposes.
The present invention will now be further illustrated by reference to the following description of drawings, synthesis of compounds and immunogens and experiments which describe specific embodiments of the invention. However, these are not to be considered as limitations to the scope of the invention defined in the claims.